(1) Field of the Invention
The present invention relates generally to the field of supporting and strengthening printed circuit boards and more particularly to a new and novel printed wiring card stiffener bracket.
(2) Description of the Prior Art
Large dimensioned printed wiring cards are subject to warpage and linear distortion once they are equipped with fairly heavy components and automatically soldered. Such distortion and warpage makes it difficult but not impossible to insert the card into a card file and also to mate properly with a respective connector. To avoid such linear distortion and warpage and also to assist in the insertion of the card, a stiffener frame or bracket is necessary.
Many support structures of the prior art such as U.S. Pat. No. 3,216,580 which issued to F. V. Fricker, Jr., on Nov. 9, 1965, U.S. Pat. No. 3,539,879 which issued to A. W. Bradley, et.al. on Nov. 10, 1970, and Swiss Pat. No. 377,902 utilize grooved wrap around frames. Such arrangements are normally unsuitable since these support structures either form a portion of the connector or the card file support frame and either interefere with the use of the printed wiring card and normal card file structures or do not provide adequate support due to the tolerances required to allow sliding of a card.
Another structure of the prior art disclosed in German Pat. No. 1,195,829 utilizes a frame type stiffener which supports the entire perimeter of the printed wiring card having engaging tabs which fit through the printed wiring card which are bent over on the opposite side of the card. Such an arrangement is normally unsuitable do to the excessive land areas required by the stiffener frame and the inconsistencies inherent in bending tabs to provide support.
The prior art stiffener bracket assembly discloses in U.S. Pat. No. 3,851,222, requires the modification of the printed wiring card by the addition of slots along the edges to engage tabs on the stiffener frame. This type of modification to the printed wiring card cannot be accomplished in the field.
Accordingly it is a principle object of the present invention to provide a printed wiring card stiffener bracket which may be utilized with standard card files and connector arrangements and with a minimum modification to the wiring card to prevent card distortion and for assisting in the insertion of the card in a card file.